TL WDR3600 wifi-ethernet bridge

Sorry for the double-post, posted in wrong category.
I had the idea of converting my TP-Link WDR3600 into a wireless adapter.
I have tried many methods, including the ones mentioned in the site.
None of them work.
I can install packages/etc. but there is no internet access from the LAN ports.

You might get sensible answers if you would describe your network topology, so that others would understand your exact needs.

Tried DD-WRT, everything worked.

Good for you, but still no hint about your actual needs.

My setup has:
Device 1, a DSL modem/WAP combo supplied by my ISP running original firmware.
Device 2, the TP-Link WDR3600 I want to convert into a wireless reciever/adapter that is connected to Device 1's wireless network.
Device 3, a device connected by Ethernet cable to Device 2.

Did you try to configure it as a routed client, or bridged? Did you use relayd or WDS?
Can we see your config files? What does "there id no internet access" exactly mean?

I tried using relayd and a routed client. The configs are gone because I switched to DD-WRT.
The 'no internet access' means I wasn't able to load any pages only using a patch cable from the switch outputs to the Ethernet port on my laptop.

Sorry, but I do not understand what do you expect from us now that you have switched to DD-WRT.

I expect only the locking of this topic.